Provision is normally made for such a device to be assembled by manufacturing said fixed portion and said moving portion of the headlight with appropriate facilities that co-operate with a screw that is installed subsequently, thereby completing the device.
It will easily be understood that such a method is burdensome in several respects.
Since the initial design includes special headlight portions having respective facilities, the facilities in question cannot be standardized. This complicates overall manufacture of the headlight to a great extent.
In addition, a device designed wherein conventional manner requires a certain number of manual operations to be performed that are difficult to automate, in particular operations relating to installing the adjustment screw between the elements it interconnects.
Documents U.S. Pat. No. 4,870,544 and EP-A-0 393 353 teach adjustment devices which although somewhat easier to install on a headlight, remain unsuitable for automated assembly.